Al-Pd alloys have shown promise for improved IC interconnect manufacturability and reliability. However, there has been little detailed evaluation of microstructure and conductor failure reported for this material. Microstructure and electromigration behaviour of Al-0.35%Pd unpassivated interconnect was studied on films deposited at 250°C or 450°C and patterned into test structures of varying width. Samples were electrically stressed to failure at l×106A/cm2 or 2×106A/cm2. At 450°C, AlPdx precipitates form while at 250°C, palladium remains in solution and a larger grain size is obtained. Slit voids were found in 1μm and 3μm wide lines, though only in the finer lines were the failures transgranular. A very large increase in lifetime of 1μm wide lines with a decrease in current density from 2×106A/cm2 to l×106A/cm2 suggests a critical current effect due to grain boundary clusters in the these lines.